The invention relates generally to improvements in rollers used in off-set printing presses, and, more particularly, to improvements in the outer surface of soft elastomeric rollers for water dampening systems and ink train rollers providing improved direction and flow control for ink and water through their respective fluid feeding systems in offset printing presses.
Offset printing presses generally have separate product feeding systems for moving water, ink and paper to and through the printing press. Typically, these systems consist of a plurality of rollers which transfer and advance the necessary water, ink, and paper webs through the printing press. Ink train systems and water dampening systems move those respective fluids by passing same from one roller to an adjacent roller and so forth, with an initial roller picking up ink or water from a pan or fountain and passing same on to an adjacent roller. Typically, the ink or water feed system for a printing press includes alternating hard or metal rollers with soft or elastomeric material rollers positioned in between and in pinching communication with the adjacent metal rollers. In the case of water and ink feed systems, the respective fluid also helps to keep the series of rollers lubricated. Relevant patents to prior art inking rollers include U.S. Pat. Nos. 1,079,339; 905,182; and 4,601,242. Patents relating to elastomeric covered rollers for use in printing rolls include U.S. Pat. Nos. 3,750,250; 4,143,092; and 4,492,012.
An elastomeric covered rigid core roller for cross stretching printing webs is disclosed in U.S. Pat. No. 4,566,162.
While these patents disclose elastomeric covered rollers for use in printing presses, and disclose certain textured surfaces for such rollers for various purposes, a need has developed for an elastomeric covered rigid core roller for use in ink and water feeding systems of printing presses having lands and grooves of specified depths, widths and spiral directions capable of improving the direction and control of fluids travelling along such ink and water feed systems, respectively. Also, a need exists for rollers which aid in milling the ink in its travels along the ink train. Such a need exists especially in present day ink feed systems wherein adjustable fountain keys positioned adjacent the fountain rollers utilize a wiping action to control direction of ink flow across cylindrically surfaced rollers in the ink train. For example, the disclosure in old prior patent 905,182 at lines 30-37 indicates that the press in which that roller is to be used does not have adjustable fountain keys.
It is therefore an object of the present invention to provide improved elastomeric covered rollers for use in offset printing presses having multi-directional spiral lands and valleys positioned thereon for providing improved flow of water and ink through their respective water and ink feed systems.